Oil and gas wells can be drilled having various configurations, such as, vertical, extended reach, deviated or horizontal, and multilateral wells. The multilateral well is a single well with one or more lateral wellbore branches that extend from a single parent wellbore into the surrounding formation. It is often desirable to monitor the physical conditions inside the lateral branches to ensure proper operations of the well.
The instrumentation of wells using fiber optics-based distributed systems, such as distributed temperature sensing (DTS), distributed acoustic sensing (DAS), and other sensing systems based on, for example, interferometric sensing is well established. Optical fiber can be run inside the well (in some cases on the outside of a tubing string), to the surface, where interrogators detect reflected light from the entire length of the fiber and/or single or multi point sensors. However, in some cases, there are structures in the well which prevent, or make difficult, fiber from being installed over the entire length of the well, or at least over all regions of interest of the well. For example, in multilateral well systems, packers or bridge plugs, or similar devices, are often used to provide hydraulic isolation of zones within the well, and wells will often include isolation of multiple zones and/or lateral branches. These packers or bridge plugs preclude passage of a fiber through the interior of the casing. As a result, it can be difficult for operators to monitor performance in the lateral branches of multilateral wells due to difficulties with providing physical communications with sensors in the lateral branches.